Bi-directional handle for a catheter

ABSTRACT

A steerable catheter or sheath includes a catheter or sheath body defining a longitudinal axis; first and second actuation wires extending from a proximal end of the body; and a control handle coupled to the body for steering a distal end of the body. The control handle includes a grip portion including a pivot; a wire diverting assembly located on the grip portion at a location separate from the pivot; and an actuator assembly coupled to the pivot and configured for pivotal movement in a single plane. The wire diverting assembly can include first and second actuation wire connection locations that are disposed on opposite sides of the longitudinal axis. The first and second actuation wires can extend toward the wire diverting assembly in a first orientation, and the wire diverting assembly can change the first orientation to a second orientation that is at an angle to the first orientation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/542,361, filed Aug. 17, 2009 (the '361 application), now pending,which is a continuation of U.S. application Ser. No. 11/115,600, filed26 Apr. 2005 (the '600 application), which is now U.S. Pat. No.7,591,784. The '361 application and the '600 application are both herebyincorporated by reference as though fully set forth herein

BACKGROUND OF THE INVENTION

a. Field of the Invention

The present invention relates to catheters and sheaths and methods ofusing catheters and sheaths. More particularly, the present inventionrelates to steerable catheter or sheath control handles and methods ofmanufacturing and using such handles.

b. Background Art

Catheters having conductive electrodes along a distal end are commonlyused for intra-cardiac electrophysiology studies. The distal portion ofsuch a catheter is typically placed into the heart to monitor and/orrecord the intra-cardiac electrical signals during electrophysiologystudies or during intra-cardiac mapping. The orientation orconfiguration of the catheter distal end is controlled via an actuatorlocated on a handle outside of the body, and the electrodes conductcardiac electrical signals to appropriate monitoring and recordingdevices that are operatively connected at the handle of the catheter.

Typically, these catheters include a generally cylindrical electricallynon-conductive body. The main body includes a flexible tube constructedfrom polyurethane, nylon or other electrically non-conductive flexiblematerial. The main body further includes braided steel wires or othernon-metallic fibers in its wall as reinforcing elements. Each electrodehas a relatively fine electrically conductive wire attached thereto andextending through the main body of the catheter. The conductive wireextends from the distal end to a proximal end where electricalconnectors such as plugs or jacks are provided to be plugged into acorresponding socket provided in a recording or monitoring device.

The distal portion of the main body is selectively deformed into avariety of curved configurations using the actuator. The actuator iscommonly internally linked to the distal portion of the catheter by atleast one actuation wire. Some catheters employ a single actuation wire,which is pulled (i.e., placed in tension) by the actuator in order tocause the distal portion of the main body to deform. Other cathetershave at least two actuation wires, where the actuation of one wire(i.e., placing one wire in tension) results in the other wire goingslack (i.e., the wire does not carry a compressive load). In suchcatheters, where the actuation wires are not adapted to carrycompressive loads (i.e., the actuation wires are only meant to be placedin tension), the actuation wires are commonly called pull or tensionwires.

To deform the distal end of the catheter into a variety ofconfigurations, a more recent catheter design employs a pair ofactuation wires that are adapted such that one of the actuation wirescarries a compressive force when the other actuation wire carries atensile force. In such catheters, where the actuation wires are adaptedto carry both compressive and tension loads, the actuation wires arecommonly called push/pull or tension/compression wires and thecorresponding catheter actuators are called push-pull actuators. U.S.Pat. No. 5,861,024 to Rashidi, which issued Jan. 19, 1999, isrepresentative of a push-pull actuator of this type, and the detailsthereof are incorporated herein by reference.

While many of the existing catheter actuators provide precise operationand good flexibility in movement of the distal portion of the body, theexisting actuators often offer a range of distal portion displacementthat is less than desirable. In other words, the amount of push/pull ofthe actuation wires (i.e., the steering travel) is often inadequate forthe medical procedure being performed. The inadequacy of the steeringtravel typically results from the generally limited size of the actuatorbody, which is usually sized for receipt and manipulation between thethumb and index finger of a user's hand. Accordingly, a need exists toprovide an improved actuating assembly for a catheter that increases theamount of steering travel associated with the actuator.

BRIEF SUMMARY OF INVENTION

In accordance with an embodiment of the disclosure, a steerable catheteror sheath can comprise a catheter or sheath body defining a longitudinalaxis; first and second actuation wires extending from a proximal end ofthe body; and a control handle coupled to the body for steering a distalend of the body. The control handle can comprise a grip portionincluding a pivot; a wire diverting assembly located on the grip portionat a location separate from the pivot; and an actuator assemblypivotally coupled to the pivot and configured for pivotal movement in asingle plane. The wire diverting assembly can comprise first and secondactuation wire connection locations that are disposed on opposite sidesof the longitudinal axis. The first and second actuation wires canextend toward the wire diverting assembly in a first orientation and thewire diverting assembly can change the first orientation to a secondorientation that is at an angle to the first orientation and divert thefirst and second actuation wires respectively to the first and secondactuation wire connection locations.

In accordance with some embodiments of the disclosure, at least aportion of each of the first and second actuation wires comprises agenerally circular cross section. In accordance with some embodiments ofthe disclosure, at least a portion of each of the first and secondactuation wires comprises a generally flat cross-section. In accordancewith some embodiments of the disclosure, at least a first portion ofeach of the first and second actuation wires comprises a generallycircular cross-section, and at least a second portion of each of thefirst and second actuation wires comprises a generally flatcross-section. In accordance with some embodiments of the disclosure, atleast one of the first and second actuation wires is formed of superelastic Nitinol. In accordance with some embodiments of the disclosure,at least a portion of at least one of the first and second actuationwires is formed of a material that permits tension or tension andcompression.

In accordance with some embodiments of the disclosure, the grip portioncomprises a first grip portion including a first surface from which thepivot extends; and a second grip portion mated with the first gripportion. The second grip portion can include a second surface. Theactuator can further comprise a slot. The wire diverting assembly canfurther comprise a portion that is configured to extend into the slot.The wire diverting assembly can further comprise first and secondbearings respectively positioned on first and second opposite sides ofthe longitudinal axis. The bearings can be annulus shaped. The first andsecond actuation wires respectively can divert about the first andsecond bearings. The wire diverting assembly can further comprise aseparating assembly for separating the actuation wires into separateplanes, and the bearings can be on opposite sides of the separatingassembly from each other. The actuation wires can cross the longitudinalaxis as they extend from their respective bearings to their respectiveactuation wire connection locations.

In accordance with some embodiments of the disclosure, a control handlefor a steerable catheter or sheath can comprise a grip portion includinga pivot, the grip portion extending along a longitudinal axis. Thecontrol handle can further comprise a wire diverting assembly located onthe grip portion at a location separate from the pivot. The wirediverting assembly can comprise first and second actuation wireconnection locations that are disposed on opposite sides of thelongitudinal axis. The control handle can further comprise an actuatorassembly pivotally coupled to the pivot and configured for pivotalmovement in a single plane. The wire diverting assembly can beconfigured to change an orientation of first and second actuation wiresfrom a first orientation in which the first and second actuation wiresare extending toward the wire diverting assembly to a second orientationthat is at an angle to the first orientation. The wire divertingassembly can also be configured to divert the first and second actuationwires respectively to the first and second actuation wire connectionlocations.

The grip portion can comprise a first grip portion including a firstsurface from which the pivot extends; and a second grip portion matedwith the first grip portion. The second grip portion can include asecond surface. The actuator can further comprise a slot. The wirediverting assembly can further include a portion that is configured toextend into the slot. The wire diverting assembly can further comprisefirst and second bearings respectively positioned on first and secondopposite sides of the longitudinal axis. The bearings can be annulusshaped. The wire diverting assembly can further comprise a separatingassembly configured to separate the actuation wires into separateplanes. The bearings can be on opposite sides of the separating assemblyfrom each other.

While multiple embodiments are disclosed, still other embodiments of thepresent invention will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the invention. As will be realized, theinvention is capable of modifications in various aspects, all withoutdeparting from the spirit and scope of the present invention.Accordingly, the drawings and detailed description are to be regarded asillustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the catheter or sheath of the presentinvention with portions of the catheter's cylindrical hollow body brokenaway to show internal components of the body.

FIG. 2 is a perspective view of the actuator handle wherein the uppergrip portion has been removed to reveal the actuation mechanism.

FIG. 3 is the same view of the handle depicted in FIG. 2, except theactuator has been removed to more fully illustrate the rest of theactuation mechanism.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective view of the catheter or sheath 10 of the presentinvention with portions of the catheter's elongated flexible generallycylindrical hollow body 12 broken away to show internal components ofthe body 12. As shown in FIG. 1, in one embodiment, the catheter 10,which is an electrophysiology, RF ablation, or similar catheter 10,includes an elongated flexible generally cylindrical hollow body 12 andan actuation handle 14 coupled to a proximal end 15 of the body 12. Aswill be understood from the following discussion, the catheter 10 isadvantageous in that the actuation handle 14 is configured tosignificantly increase the steering travel of the distal end 16 of thebody 12, as compared to prior art actuation handles.

In one embodiment, the body 12 is typically polyurethane, nylon or anysuitable electrically non-conductive material. The body 12 serves as atleast a portion of the blood-contacting segment of the catheter 10 andis vascularly inserted into a patient by methods and means well known inthe art.

As illustrated in FIG. 1, the distal end 16 of the body 12 includesplural spaced electrodes 18. Each electrode 18 is connected to a fineelectrical conductor wire that extends through the body 12 and thehandle 14. An electrical plug extends from the proximal end of thehandle 14 and is adapted to be inserted into a recording, monitoring, orRF ablation device.

As indicated in FIG. 1, the body 1-2 includes actuation wires 20, 22that extend longitudinally in a side-by side relationship through thebody 12 and into the handle 14. The handle 14 is used to displace theactuation wires 20, 22 to manipulate the distal end 16 of the body 12into a variety of configurations and shapes to perform intravasculartesting and ablation procedures. The distal ends of the actuation wires20, 22 are coupled to the distal end 16 of the body 12, and the proximalend of the actuation wires 20, 22 are coupled to the handle's actuationmechanism.

In one embodiment, the actuation wires 20,22 are formed from a superelastic Nitinol wire or another suitable material. In one embodiment,the actuation wires 20,22 have a generally flat cross section, acircular cross section, or a combination of cross-sectional shapes alongtheir length. For example, in one embodiment, the actuation wires 20, 22are generally circular in cross-section along a substantial portion ofthe wire and have a flattened ribbon-like portion near the distal end 16of the body 12.

In one embodiment, each actuation wire 20, 22 resides in a lumen or tubethat runs generally the full length of the body 12 and helps to guidethe actuation wire 20, 22 and prevent the actuation wire 20, 22 frombuckling. In one embodiment, the actuation wires 20,22 are pull ortension wires 20, 22 (i.e., the actuation wires 20, 22 are not adaptedto support a compressive load). In another embodiment, the actuationwires 20,22 and the lumens are configured such that the actuation wires20, 22 are pull/push or tension/compression wires 20, 22 (i.e., theactuation wires 20,22 are adapted to support a compressive load). Thus,when one actuation wire 20,22 is placed in tension, the other actuationwire 20, 22 will carry a compressive load. This is advantageous becauseit allows for a decreased number of catheter components and increaseddeflection control of the distal end 16 of the body 12.

As shown in FIG. 1, the actuation handle 14 includes a distal end 24coupled to the proximal end 15 of the body, a proximal end 26, an uppergrip portion 28 coupled to a lower grip portion 30, and an actuationmechanism that includes an actuator 32 movably mounted to the gripportions 28, 30. As can be understood from FIG. 1, an operator canmanipulate the distal end 16 of the body 12 by selectively moving theactuator 32 relative to the grip portions 28, 30.

As illustrated in FIG. 1, in one embodiment, the actuation handle 14 hasa generally elongated rectangular shape. In other embodiments, theactuation handle 14 will employ other configurations without departingfrom the scope and intent of the invention.

For a detailed discussion of the handle's actuator 32 and itsrelationship to other portions of the actuation mechanism 34 and thegrip portions 28, 30, reference is now made to FIG. 2. FIG. 2 is aperspective view of the actuator handle 14 wherein the upper gripportion 28 has been removed to reveal the actuation mechanism 34. Asshown in FIG. 2, in one embodiment, the actuator 32 includes a top plate36, a bottom plate 38, and ribs 40, 42 (shown in phantom lines). Eachplate 36, 38 has an outer planar surface 36 a, 38 a and an inner planarsurface 36 b, 38 b. The actuator 32 is configured such that the innerplanar surfaces 36 b, 38 b are opposed and generally parallel to eachother.

As illustrated in FIG. 2, in one embodiment, the actuator 32 isgenerally semi-circular in shape such that the actuator 32 has a distalgenerally linear side or edge 44 and a proximal generally arcuate sideor edge 46 that extends between the ends of the generally linear side oredge 44. As indicated in FIG. 2, in one embodiment, each plate 36, 38includes a pivot hole 48, 50 that is located near, and centered along,the linear side 44. In one embodiment, the radius of the arcuate side 46is generally measured from the center of the pivot holes 48, 50.

As indicated in FIG. 2, the ribs 40, 42 are generally perpendicular to,and extend between, the inner planar surfaces 36 b, 38 b to interconnectthe plates 36, 38 to each other to form an integral actuator 32. Asillustrated via phantom lines in FIG. 2, in one embodiment, the ribs40,42 extend from their respective ends of the linear side 44 towardsthe pivot holes 48, 50. The ribs 40, 42 are configured such that theactuator may pivot about the pivot holes 48, 50 and relative to the gripportions 28, 30 without abutting against a wire guide 52 and theactuation wires 20, 22, which pass generally perpendicularly through theaxis of the pivot holes 48, 50, as described later in this DetailedDescription. For example, as indicated in FIG. 2 by phantom lines, toprovide adequate clearance for actuator pivoting, the ribs 40, 42terminate prior to reaching the pivot holes 48,50. Additionally, theribs 40,42 taper down as they extend towards the pivot holes 48, 50 suchthat the linear sides or edges 44 of each plate 36, 38 extend distallypast the ribs 40, 42 (i.e., the ribs 40, 42 are recessed relative to thelinear sides or edges 44 of each plate).

As shown in FIG. 2, a slot 53 in the actuator 32 is defined between theinner planar surfaces 36 b, 38 b. The slot 53 extends distally from thearcuate side 46 of the actuator 32 towards the ribs 40, 42. As theactuator 32 is pivoted relative to the grip portions 28, 30, the slot 53allows the upper and lower plates 36, 38 to pass over and under,respectively, the actuation wires 20, 22, the wire guide 52, and thedistal ends of a pair of wire dividers 54, 56, as will now be describedin the following discussion of FIG. 3.

FIG. 3 is the same view of the handle depicted in FIG. 2, except theactuator 32 has been removed to more fully illustrate the rest of theactuation mechanism 34. As illustrated in FIG. 3, in one embodiment, thelower grip portion 30, which is generally a mirror image of the uppergrip portion 28 (i.e., the discussion of the features of the lower gripportion 30 is generally equally applicable to the features of the uppergrip portion 28), includes a recessed planar area 60 defined between adistal planar area 62 and a proximal planar area 64. A distal groove 66extends through the distal planar area 62 along the longitudinalcenterline L of the lower grip portion 30. Similarly, a proximal groove68 extends through the proximal planar area 64 along the longitudinalcenterline L of the lower grip portion 30. When the upper and lower gripportions 28, 30 are mated together to form the handle 14, the distal andproximal planar areas 62,64 of the upper grip portion 28 matingly abutagainst their respective planar areas 62, 64 of the lower grip portion30, and the grooves 66, 68 in each grip portion 28, 30 combine to form achannel, lumen or pathway that, in one embodiment, is coaxial with thelongitudinal axis of the handle 14 and extends through the handle 14.

For example, as indicated in FIG. 3, the distal groove 66 serves as halfof the pathway through which the actuation wires 20,22, the centrallumen of the body 12 (if any), and the wires leading to the electrodes18 pass on their way to the proximal end 26 of the handle 14 (the distalgroove 66 in the upper grip portion 28 would serve as the other half ofsaid pathway). Likewise, the proximal groove 68 serves as half of thepathway through which the central lumen of the body 12 and the wiresleading to the electrodes 18 pass on their way to the proximal end 26 ofthe handle 14 (the proximal groove 68 in the upper grip portion 28 wouldserve as the other half of said pathway).

As shown in FIG. 3, a pair of oblique walls 70, 72 obliquely convergetowards the longitudinal centerline L of the lower grip portion 30 andextend generally perpendicularly upwards from the recessed planar area60 to the distal planar area 62. The oblique walls 70, 72 serve as anabutment for the linear side or edge 44 of the actuator 32 to preventthe actuator from over pivoting relative to the grip portions 28, 30. Inother words, the oblique walls 70, 72 serve as mechanical stops to limitmovement of the actuator 32 in opposite directions from the actuator'scentral undeflected position depicted in FIGS. 1 and 2.

As illustrated in FIG. 3, in one embodiment, a pivot 74 extendsgenerally perpendicularly from the recessed planar area 60 in a locationthat is near the convergence of the oblique walls 70, 72. The pivot 74is a cylindrical member that is received within the pivot holes 48, 50of the actuator 32 (see FIG. 2) and serves as a pivot about which theactuator 32 may pivot. In one embodiment, the axis of the pivot 74 iscentered along the longitudinal centerline L of the lower grip portion30, and the pivot 74 includes a pivot groove 76 that is aligned with thelongitudinal centerline L in manner similar to that described withrespect to the distal and proximal grooves 66, 68. When the upper andlower grip portions 26, 38 are matingly joined together, the end planarsurface of the upper grip portion's pivot matingly abuts against the endplanar surface of the lower grip portion's pivot 74.

As shown in FIG. 3, in one embodiment, a wire guide or tube 52 extendsfrom the distal groove 66 to, and through, the pivot groove 76. The wireguide 52 serves to maintain the actuation wires 20, 22 in an alignmentthat is generally parallel with the longitudinal centerlines L of thegrip portions 36, 38. As illustrated in FIG. 3, a space exists betweenthe wire guide 52 and the recessed planar area 60. Thus, as previouslymentioned, the portion of the bottom plate 38 that defines the mostproximal edge of the pivot hole 50 may displace through the spacebetween the wire guide 52 and the recessed planar area 60 when theactuator 32 pivots about the pivot 74. A similar configuration existsbetween the wire guide 52 and the recessed planar area of the upper gripportion 28 for accommodating the displacement of the portion of the topplate 36 that defines the most proximal edge of the pivot hole 48 whenthe actuator 32 pivots about the pivot 74.

As illustrated in FIG. 3, a pair of peripheral walls 78, 80 extend fromthe proximal planar area 64 along the side edges of the proximal portionof the recessed planar area 60. As indicated in FIG. 3, to define a gap82 (see FIG. 1) between the upper and lower grip portions 28, 30 throughwhich the actuator 32 may laterally displace relative to the grips 28,30when the grips 28, 30 are mated together, the peripheral walls 78, 80 donot extend along the full length of the side edges of the recessedplanar area 60.

As shown in FIG. 3, a pair of bearing assemblies 90, 92 are locatedbetween the peripheral walls 78, 80 in the proximal portion of therecessed planar area 60. Each bearing assembly 90, 92 is positioned onan opposite side of the longitudinal centerline L of the lower gripportion 30. As illustrated in FIG. 3, the bearing assemblies 90, 92serve to divert the actuation wires 20,22 from an orientation that isgenerally parallel to the centerlines L of the grip portions 28, 30 toan orientation that is generally non-parallel (e.g., oblique and/orperpendicular) to the centerlines L as the actuation wires 20, 22 extendthrough the distal groove 66, through the wire guide 52, about therespective bearing assemblies 90, 92 and out to their respective pointsof connection to the actuator 32.

As indicated in FIG. 3, each bearing assembly 90, 92 includes an upperannulus shaped bearing 94, 96 and a lower annulus shaped bearingcoaxially rotateably mounted on an axle 98, 100 and separated from eachother by a wire divider 54, 56. In one embodiment, the axles 98, 100 aregenerally perpendicular to the longitudinal centerline L and therecessed planar area 60. The upper extreme ends of each axle 98, 100extend upward into receiving holes in the recessed planar area of theupper grip portion 36. Similarly, the lower extreme ends of each axle98, 100 extend downward into receiving holes in the recessed planar area60 of the lower grip portion 38. Thus, each bearing assembly 90, 92 withits respective upper bearing 94, 96, lower bearing, and wire divider 54,56 is held in place as an integral unit within the gap 82 definedbetween the upper and lower grip portions 36, 38. As can be understoodfrom FIG. 3, the arrangement of the annulus shaped upper bearings 94, 96and their respective axles 98, 100 is a mirror image of the annulusshaped lower bearings and their respective axles 98, 100.

As illustrated in FIG. 2, the bearing assemblies 90, 92 are positionedsuch that the portions of the wire dividers 54, 56 that are locateddistal to the annulus shaped bearings 94, 96 extend into the slot 53,and the annulus shaped bearings 94, 96 are located proximal to thearcuate side 46 of the actuator 32. In other words, in one embodiment,the distal portions of the wire dividers 54, 56 extend into the slot 53.As a result, the top and bottom plates 36,38 displace over and under,respectively, the distal portions of the wire dividers 54, 56 as theactuator 32 pivots about the pivot 74.

As shown in FIG. 3, each wire divider 54, 56 is elongated and has smoothedges or contoured surfaces to prevent abrasion of the actuation wires20, 22 as they displace against the wire dividers 54, 56. In oneembodiment, the wire dividers 54, 56 have an elliptical shape with themajor axis parallel to the longitudinal centerlines L of the gripportions 36, 38. The wire dividers 54, 56 elevationally separate theactuation wires 20, 22 into generally parallel planes as the actuationwires 20, 22 cross over each other when being diverted about theirrespective bearing assemblies 90, 92.

As can be understood from FIG. 3, the actuation wires 20,22 enter thehandle 14 from the body 12 and travel through the distal groove 66 andthe wire guide 52 in substantially one plane. The actuation wires 20, 22begin to separate into parallel planes as they proceed towards the wiredividers 54, 56. As the actuation wires 20, 22 proceed about the bearingsurfaces of the lower and upper bearings 94, 96, the first actuationwire 22 passes against the top surface of the wire dividers 54, 56, andthe second actuation wire 20 passes against the bottom surface of thewire dividers 54, 56.

As indicated in FIGS. 1-3, in one embodiment, the actuation wires 20, 22enter the handle 14 from the body 12 and extend through the distalgroove 66 and the wire guide 52 in an orientation that is generallyparallel to the centerlines L of the grip portions 28, 30. Asillustrated in FIG. 3, in one embodiment, as the actuation wires 20, 22exit the wire guide 52 on their way to their respective bearingassemblies 90, 92, the actuation wires 20, 22 begin to diverge away fromeach other. Also, as indicated in FIG. 2, as the actuation wires 20, 22pass through the wire guide 52 and on to their respective bearingassemblies 90, 92, the actuation wires 20, 22 pass through the actuator32 (i.e., through the slot 53 defined by the top and bottom plates 36,38).

As shown in FIG. 3, in one embodiment, a first actuation wire 22 extendsfrom the wire guide 52, passes over a first wire divider 56, and firstencounters a first upper bearing 96 on the side of the first upperbearing 96 that is on the opposite side of the first upper bearing'saxle 100 from the longitudinal centerline L of the lower grip portion30. The first actuation wire 22 then extends about the first upperbearing 96 (thereby changing from an orientation that was generallyparallel to the centerline L to an orientation that is non-parallel,e.g., oblique and/or perpendicular, to the centerline L) and passesagainst the second upper bearing 94 as the first actuation wire 22passes between the two upper bearings 94, 96 on the first actuationwire's way to its point of connection to the actuator 32. On the firstactuation wire's way to its point of connection with the actuator 32(after leaving the second upper bearing 94) the first actuation wire 22again passes through the slot 53 and connects to the actuator 32 near anextreme outer end of a first rib 40 (see FIG. 2).

As can be understood from FIG. 3, in a manner similar to that justdescribed, the second actuation wire 20 extends from the wire guide 52,passes below the second wire divider 54, and first encounters a firstlower bearing on the side of the first lower bearing that is on theopposite side of the first lower bearing's axle 98 from the longitudinalcenterline L of the lower grip portion 30. The second actuation wire 20then extends about the first lower bearing (thereby changing from anorientation that was generally parallel to the centerline L to anorientation that is generally non-parallel, e.g., oblique and/orperpendicular, to the centerline L) and passes against the second lowerbearing as the second actuation wire 20 passes between the two lowerbearings on the second actuation wire's way to its point of connectionto the actuator 32. On the second actuation wire's way to its point ofconnection with the actuator 32 (after leaving the second lower bearing)the second actuation wire 20 again passes through the slot 53 andconnects to the actuator 32 near an extreme outer end of a second rib 42(see FIG. 2).

As can be understood from the FIG. 3 and the immediately precedingdescription, in one embodiment, each actuation wire 20, 22 starts on afirst side of the longitudinal centerline L as the actuation wire 20, 22travels along the distal groove 66 and the wire guide 52 on its way toits respective bearing assembly 90, 92. However, once each actuationwire 20,22 encounters its respective bearing assembly 90, 92, theactuation wire 20, 22 is diverted such that the actuation wire 20, 22passes onto the other side of the longitudinal centerline L. Thisembodiment is advantageous because it maximizes the extent to which theactuation wires 20, 22 can be displaced by the actuator.

In other embodiments where less actuation is required, the actuationwires 20,22 will not pass from one side of the longitudinal centerline Lto the other as the actuation wires 20, 22 are diverted about theirrespective bearing assemblies 90, 92. For example, where the firstactuation wire 22 is extended between the upper bearings 94, 96 prior torouting about the first upper bearing 96, and the second actuation wire20 is extended between the lower bearings prior to routing about thefirst lower bearing, the actuation wires 20, 22 will not cross thelongitudinal centerline L.

In use, the body 12 is inserted into the patient in a manner well knownin the art. An operator grasps the handle 14 and manipulates theactuator 32 between his thumb and finger. Advantageously, the actuator32 protrudes from each side of the handle 14 to allow for such ease ofmovement and manipulation. The actuator 32 is moved relative to thehandle 14, which causes the actuation wires 20, 22 to be displaced aboutthe bearing assemblies 90, 92. As a result, the distal portion 16 of thebody 12 deflects.

Although the present invention has been described with reference topreferred embodiments, persons skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention. The invention is limited only by the scopeof the following claims.

1. A steerable catheter or sheath comprising: a catheter or sheath bodydefining a longitudinal axis; first and second actuation wires extendingfrom a proximal end of the body; and a control handle coupled to thebody for steering a distal end of the body, the control handlecomprising: a grip portion including a pivot; a wire diverting assemblylocated on the grip portion at a location separate from the pivot, thewire diverting assembly comprising first and second actuation wireconnection locations that are disposed on opposite sides of thelongitudinal axis; an actuator assembly pivotally coupled to the pivotand configured for pivotal movement in a single plane, wherein the firstand second actuation wires extend toward the wire diverting assembly ina first orientation and the wire diverting assembly changes the firstorientation to a second orientation that is at an angle to the firstorientation and diverts the first and second actuation wiresrespectively to the first and second actuation wire connectionlocations.
 2. The catheter or sheath of claim 1, wherein at least aportion of each of the first and second actuation wires comprises agenerally circular cross section.
 3. The catheter or sheath of claim 1,wherein at least a portion of each of the first and second actuationwires comprises a generally flat cross-section.
 4. The catheter orsheath of claim 1, wherein at least a first portion of each of the firstand second actuation wires comprises a generally circular cross-sectionand wherein at least a second portion of each of the first and secondactuation wires comprises a generally flat cross-section.
 5. Thecatheter or sheath of claim 1, wherein at least one of the first andsecond actuation wires is formed of super elastic Nitinol.
 6. Thecatheter or sheath of claim 1, wherein at least a portion of at leastone of the first and second actuation wires is formed of a material thatpermits tension or tension and compression.
 7. The catheter or sheath ofclaim 1, wherein the grip portion comprises: a first grip portionincluding a first surface from which the pivot extends; and a secondgrip portion mated with the first grip portion, wherein the second gripportion includes a second surface.
 8. The catheter or sheath of claim 1,wherein the actuator further comprises a slot.
 9. The catheter or sheathof claim 8, wherein the wire diverting assembly further comprises aportion that is configured to extend into the slot.
 10. The catheter orsheath of claim 1, wherein the wire diverting assembly further comprisesfirst and second bearings respectively positioned on first and secondopposite sides of the longitudinal axis.
 11. The catheter or sheath ofclaim 10, wherein the bearings are annulus shaped.
 12. The catheter orsheath of claim 11, wherein the first and second actuation wiresrespectively divert about the first and second bearings.
 13. Thecatheter or sheath of claim 12, wherein the wire diverting assemblyfurther comprises a separating assembly for separating the actuationwires into separate planes, and wherein the bearings are on oppositesides of the separating assembly from each other.
 14. The catheter orsheath of claim 12, wherein the actuation wires cross the longitudinalaxis as they extend from their respective bearings to their respectiveactuation wire connection locations.
 15. A control handle for asteerable catheter or sheath, the control handle comprising: a gripportion including a pivot, the grip portion extending along alongitudinal axis; a wire diverting assembly located on the grip portionat a location separate from the pivot, the wire diverting assemblycomprising first and second actuation wire connection locations that aredisposed on opposite sides of the longitudinal axis; an actuatorassembly pivotally coupled to the pivot and configured for pivotalmovement in a single plane, wherein the wire diverting assembly isconfigured to change an orientation of first and second actuation wiresfrom a first orientation in which the first and second actuation wiresare extending toward the wire diverting assembly to a second orientationthat is at an angle to the first orientation, and wherein the wirediverting assembly is configured to divert the first and secondactuation wires respectively to the first and second actuation wireconnection locations.
 16. The control handle of claim 15, wherein thegrip portion comprises: a first grip portion including a first surfacefrom which the pivot extends; and a second grip portion mated with thefirst grip portion, wherein the second grip portion includes a secondsurface.
 17. The control handle of claim 15, wherein the actuatorfurther comprises a slot.
 18. The control handle of claim 17, whereinthe wire diverting assembly further includes a portion that isconfigured to extend into the slot.
 19. The control handle of claim 15,wherein the wire diverting assembly further comprises first and secondbearings respectively positioned on first and second opposite sides ofthe longitudinal axis, and wherein the bearings are annulus shaped. 20.The control handle of claim 19, wherein the wire diverting assemblyfurther comprises a separating assembly configured to separate theactuation wires into separate planes and the bearings are on oppositesides of the separating assembly from each other.